Electric vehicles are known having battery packs which drive an electric motor which in turn drives the vehicle wheels. Two types of vehicles are known using electric motors, the first is a hybrid electric vehicle where the vehicle includes an electric motor and an onboard fuel driven engine, where the engine is used to drive the wheels under certain vehicle circumstances.
Another type of electric vehicle also has an onboard fuel driven engine, but the engine is only used to drive a generator, which in turn charges the batteries. The latter type arrangement is referred to as range extender as the onboard engine/generator extends the range that the vehicle can travel on the battery pack before a complete recharge.
With this type of hybrid vehicle, also called electric vehicle with Range Extender, a combustion engine is coupled to an electric machine acting as a generator. The combustion engine delivers its power to the generator, which transforms the rotary motion into electric energy and supplies it to the battery to extend the range (travelling distance of a vehicle without external charge). Alternatively, the electrical energy could be connected to an electric traction motor of the vehicle. In this manner the combustion engine can be operated with a very good efficiency in all operating aspects, which has a positive effect on CO2 emissions and fuel consumption of the aggregate. Multiple aspects of a range extender design and operation in a vehicle are addressed in this application.
A first factor of such aggregates is the coupling of the combustion engine to the generator, because the high combustion power of the engine causes substantial rotary imbalances and deformation on the crank shaft. In general, in order to couple a generator to a combustion engine, several solutions are known today, whereby the design of the generator plays an important role. The known solutions, e.g. according to DE 197 35 021 A1 or DE 10 2007 024 126 A1, concern applications in so-called parallel hybrid vehicles which have a complex coupling system in which the coupling parts are coupled axially.
Various solutions for the connection of the generator shaft with the crank shaft may be envisaged, for example an elastomer coupling could be provided, which however requires very much space axially as well as radially, and large tolerances must be chosen. These couplings also cannot absorb the required increasing dynamic torque.
Other connections include connection of the shafts through a cone or tapered coupling. The connections provide a rigid connection, but need space in length and diameter in order to have enough rigidity. Furthermore, axial tolerances are problematic because during the assembly, the mounting position dependent on the tightening torque cannot be exactly determined. Assembly and removal are also made more difficult.
Other connections include connection of the shafts through internal teeth. These connections however are complex to manufacture; the generated momentum provoke a mechanical play and running noise if a thrust tolerance is used; assembly and removal are problematic with crimp connections; and assembly length/space requirements are relatively high.
Based on this state of the art, it is an object of the invention to provide a serial hybrid electric vehicle in which the connection between the combustion engine and the generator is very precisely adjusted and has a torsion-resistant design, yet enabling both weight savings and easy assembly.
Another object is to enable an efficient length adjustment of the generator shaft and the crank shaft in case of variations in temperature.
Another object is to enable the generator to serve as the flywheel mass of the engine, reducing both the cost and the weight.
Another object is to provide minimum weight to the engine by eliminating such peripheral components as a tradition oil pump. Rather, a method of providing a “pump” from suction created during the compression stroke is shown herein.
Another object is to provide components within the engine requiring minimal lubrication.
Another object is to provide an engine design having a “run-ready” condition.
Another object is to provide an optimized heating/cooling system for the range extender and vehicle.
With the present design in accordance with the drawings, the generator is suitable for the mounting to different engines, whereby the coupling can in principle be made by any chosen connection of the shafts and the housing. Engine and generator are independent and are connected by a connecting member. For a single-cylinder engine with a very short crank shaft, this design is the most sensible solution because of the separate bearing of the generator rotor allows the air gap in the generator to be kept small in order to achieve a high efficiency. The bending moment in the crank shaft during combustion, as well as the bearing clearances on the short distance between the bearings can in an appropriate arrangement be carried by the generator bearing, thus preventing contact of the rotor and the housing.
Depending on the design and the stability of the shaft connection between the combustion engine and the generator, the generator may serve as a flywheel mass for the combustion engine, which is however not without difficulty because of the generated momentum, but is solved, with the solution at hand.
The present disclosure relates to an engine/generator and the control mechanism for a range extender engine.
In one embodiment, a serial hybrid electric vehicle is coupled with a combustion engine which serves to extend the operating range. The combustion engine is coupled to the generator of the range extender by a self-centering spur gearing.
In another embodiment of the invention, a serial hybrid electric vehicle is coupled with combustion engine which serves to extend the operating range. A crankshaft of the engine is fixedly connected to a shaft of the generator. A fixed bearing and a first floating bearing are located on the side of the generator and the bearings on the side of the engine are configured as floating bearings in order to absorb the length extensions of the shafts caused by temperature influence.
In another embodiment of the invention, a combustion engine, comprises a crankcase defining a journal area and an oil sump; a cylinder communicating with the crankcase; a cam chain chamber discrete from the crankcase; a crankshaft journalled in the journal area of the crankcase, with a first end extending into the cam chain chamber and a second end extending through the crankcase; a piston positioned in the cylinder; a connecting rod coupling the piston to the crankshaft; a head above the cylinder having at least one cam therein operating valves in the head; a first gear positioned on the crankshaft first end and positioned in the cam chain chamber; a second gear positioned on an end of the cam; a chain entrained around the first and second gear; a passageway defined between the oil sump and the crankshaft; wherein, when the piston is moving from a bottom dead center position to a top dead center position, a vacuum is created, siphoning oil through the passageway to lubricate at least a portion of the crankshaft.
In another embodiment of the invention, a combustion engine, comprises a crankcase defining a journal area and an oil sump; a cylinder communicating with the crankcase; a cam chain chamber discrete from the crankcase; a crankshaft journalled in the journal area of the crankcase, with a first end extending into the cam chain chamber and a second end extending through the crankcase; a piston positioned in the cylinder; a connecting rod coupling the piston to the crankshaft; a head above the cylinder having at least one cam therein operating valves in the head; a first gear positioned on the crankshaft first end and positioned in the cam chain chamber; a second gear positioned on an end of the cam; a chain entrained around the first and second gear; a port communicating between the crankcase and the cam chain chamber; and a valve allowing the flow of blow by gases and compressed gases into the cam chain chamber when the piston is moving from a top dead center position to a bottom dead center position.
In another embodiment of the invention, a combustion engine comprises a vehicle, comprising: an electric propulsion drive assembly; a first cooling circuit for the electric propulsion drive assembly; an engine, including a crankcase having an oil sump; and a pre-heater for the oil sump in fluid communication with the first cooling circuit for pre-heating engine oil.
In another embodiment of the invention, a combustion engine comprises a crankcase having an oil sump; and a pre-heater for pre-heating engine oil in the oil sump, the pre-heater being integrated with the oil sump of the crankcase.
In another embodiment of the invention, a combustion engine comprises a crankcase defining a journal area and an oil sump; a cylinder communicating with the crankcase; a cam chain chamber discrete from the crankcase; a crankshaft journalled in the journal area of the crankcase, with a first end extending into the cam chain chamber and a second end extending through the crankcase; a piston positioned in the cylinder; a head above the cylinder having at least one camshaft therein operating valves in the head; a first gear positioned on the crankshaft first end and positioned in the cam chain chamber; a second gear positioned on an end of the cam; a chain entrained around the first and second gear; and an oil distribution mechanism for distributing oil in the oil sump onto the cam chain for delivering lubrication oil to the head.
In another embodiment of the invention, a combustion engine comprises a crankcase defining a journal area and an oil sump; a cylinder communicating with the crankcase; a cam chain chamber discrete from the crankcase; a crankshaft journalled in the journal area of the crankcase, with a first end extending into the cam chain chamber and a second end extending through the crankcase; a piston positioned in the cylinder; a head above the cylinder having at least one camshaft therein operating valves in the head; a first gear positioned on the crankshaft first end and positioned in the cam chain chamber; a second gear positioned on an end of the cam; a chain entrained around the first and second gear; and an oil distribution mechanism or member for distributing oil in the oil sump onto the cam chain for delivering lubrication oil to the head.
In another embodiment of the invention, a control system is provided for an electric vehicle, where the electric vehicle includes a drive axle coupled to a chassis. The control system comprises an engine generator including an electrical machine driven by an engine, the engine generator being configured to generate electrical power; a controller configured to electronically control the engine of the engine generator; an electric motor configured to drive the drive axle of the electric vehicle; a battery configured to drive the electric motor and to receive the electrical power generated by the engine generator; and a mode selection device in communication with the controller for selecting one of a plurality of operating modes of the engine generator, the plurality of operating modes providing variable rates of electrical power generation.
An inventive method of controlling an engine of an electric vehicle including a generator driven by the engine and an electric motor driven by an onboard battery, the method includes the steps of: monitoring a vehicle speed of the electric vehicle; starting the engine of the electric vehicle when the vehicle speed increases to a first predetermined threshold; generating electrical power with the generator for use by the electric vehicle; and stopping the engine of the electric vehicle when the vehicle speed decreases to a second predetermined threshold.
An inventive method of controlling an engine of an electric vehicle including a generator driven by the engine and an electric motor driven by an onboard battery, the method includes the steps of: providing a vehicle control unit for controlling an electrical system of the electric vehicle, the electrical system including the electric motor and the battery; driving the electric motor with the battery; monitoring a plurality of parameters of the battery with the vehicle control unit, the plurality of parameters including at least one of a voltage level, a charge level, and a temperature level; starting the engine of the electric vehicle when each of the plurality of parameters of the battery are below a predetermined minimum threshold; generating electrical power with the generator for use by the electric vehicle; and charging the battery of the electric vehicle with the generated electrical power.
An inventive method of charging a battery of an electric vehicle, the electric vehicle including a generator driven by an engine and an electric motor driven by the battery, the electric motor being configured to drive a drive axle of the electric vehicle to move the electric vehicle. The method includes the steps of providing a regenerative braking system with the electric vehicle, the regenerative braking system being configured to transfer kinetic energy of the electric vehicle to the electric motor to rotate the electric motor in a reverse direction; rotating the electric motor in a forward direction with electrical power from the battery to move the electric vehicle; generating a first electrical current with the generator, the first electrical current being routed to the battery; rotating the electric motor in a reverse direction with the regenerative braking system to slow movement of the electric vehicle and to generate a second electrical current, the second electrical current being routed to the battery; charging the battery with the first and second electrical currents; monitoring the first and second electrical currents during the charging step to determine a total electrical current supplied to the battery; and removing the first electrical current from the battery upon the total electrical current exceeding a first predetermined threshold.
In another embodiment, an electric vehicle, comprises a chassis; a drive axle coupled to the chassis; an electric motor configured to drive the drive axle; a battery configured to drive the electric motor; an engine generator configured to generate electrical power and to provide electrical power generated to the battery; and a mass supported by the engine to dampen vibrations of the engine.
Finally, a method of controlling an engine of an electric vehicle, where the electric vehicle includes a generator driven by the engine, an electric motor driven by a battery, and a transmission having a plurality of gears, the method including the steps of: monitoring a vehicle speed of the electric vehicle; placing the transmission of the electric vehicle in a neutral gear; receiving a user input configured to activate the engine of the electric vehicle; starting the engine of the electric vehicle upon receipt of the user input and upon the vehicle speed of the electric vehicle being at or below a predetermined threshold value; generating electrical energy with the generator; routing the electrical energy to the battery; and charging the battery of the electric vehicle with the generated electrical energy.
The invention will now be explained in more detail in the following by means of drawings of an exemplary embodiment, where: